Machine for grinding tools



S. A. COGSDILL MACHINE FO Nov. 23, 1937.

R @BINDING TOLS Filed Aug. 5,

1935 2 Sheets-Sheet l mvENrQ STUART A. COGSDILL ATTORNEYS Nov., 23, 1937. s. A. coGsDlLL MACHINE FCR GRINDING TOOLS 2 Sheets-Sheet 2 Filed Aug. 5, 1935 STUART A.COGSDILL ATTO RNEYS Patented Nov. 23, 1937 UNITED `STATES PATENT OFFICE Cossdill Manufacturing Company, Inc., De-

\ troit, Mich., a corporation of Michigan Application August 5,` 1935;- Serial No. 34,818

7 Claims.

The invention relates to machines for grinding tools and has for one of its objects to provide an improved machine for automatically forming a tool with radial relief. 'Ihe invention has for 5 another object to provide a machine with adjustable means for varying the radial relief. The invention has for further objects to so construct the machine that it operates accurately within Very close limits and that its parts are readily l accessible.

These and other objects of the invention will become apparent from the following description, taken in connection with the accompanying drawings, in which I l Figure l is a front elevation, partly in section,

of a machine embodying my invention;

Figure 2 is an end view thereof;

Figure 3 is a plan view, partly in-section, thereof 20, Figure 4 is an elevation of one of the cams;

Figure 5 is an enlarged side elevation of the tool;

Figure 6 is a cross section on the line 6-6 of Figure 5.

As illustrated in the present instance, the machine is designed to grind combined drills and countersinks, although it is apparent that the 'machine may be used to grind other tools.

I is the base of the machine and 2 is the support for the tool 3.. The support is rockably mounted upon the base and. 'is adapted to carry the tooll into engagement with the abrasive member or grinding wheel 4, which is suitably driven. While the form of the abrasive member or grinding wheel will, of course, vary with the particular tool to be operated upon, it is shown as having the beveled portion 5 for grinding the countersink part 6 of the tool and the cylindrical portion 'I for grinding the drill part 8 of the For rockably mounting the support upon the base, I have provided the pivot member 9 which extends longitudinally through the lower portion of the support and is xedly secured theretoas by having a press t therewith. I have also provided the anti-frictionl bearings I0 and I I mounted in the base and located at opposite ends of the pivot member, the bearing I0 being antithrust in an axial direction. This bearing is formed, as shown, of two sets of tapered roller bearings with their inner and outer races. It is held from axial movement relative to the base by means of the annular projection I2 formed on the base and located between the outer races. The innervrace of the inner set is engageable With the annular shoulder I3 `formed upon the pivot member and the inner race of the outer set is engageable with the nut I4 threaded upon the pivot member. The arrangement is such, therefore, that the pivot member and support 5 areheld from longitudinal or axial movement relative to the support.

I5 is the holder for the tool 3, this holder having the collapsible ared end portion I6 for engaging the tool. I8 is the work spindle jourl0 naled in the bearings I9 located in the support. This work spindle encircles and carries the holder I5 and also drives the holder by means of the key 20. The portion of the spindle adapted to encircle the ared end portion I'E of the holder l5 is internally ilared so that upon axial movement of the holder in a direction toward the abrasive member or grinding wheel its flared portion may expand to release the tool, while upon axial movementin theopposite direction its flared portion 20 will be contracted to grip the tool. Thetool is predeterminedly positioned in the holder by suitable means which, as shown. in the present instance, includes the projection I'I adapted to-be engaged by a loading device. 25

The holder I5 is adapted to be moved axially relative to the spindle I8 and away from the abrasive member or grinding wheel 4 by the draw bar 2I which extends within the spindle and is connected to the holder. The exposed end of 30 the draw bar is connected to the block 22 which is adapted to be forced outwardly by the collar 23. This collar is located between the block 22 and the nose.24 of the collar 25, which lat' er is axially slidably mounted upon the spindle I8 '35 and is adapted to be axially moved by means of the yoke 26. This yoke is pivoted upon the support2 intermediate its ends and it has furcations at one end pivotally connected to the collar 25 and a ball at the other end slidable in the 40 cam 21 mounted upon the base I. The cam is arranged toactuate the yoke andv thereby to force the block 22 outwardly upon swinging of the support 2 from its inoperative position upwardly to its operative position, shown in Fig- 45 '.re 2. For frictionally holding the draw bar in its outward position, the nose 24 is provided with the beveled end portion 24' and the cylindrical portion 242 and this nose is engageable by the long arms 28 of the bell cranks 28, which` latter 50 are pivotally mounted at diametrically opposite sides of the block 22. Suitable compression coil springs 29 between the block 22 and the short arms 282 of the bell cranks yieldably urge the A long arms into frictional engagement with the 55 84 is a pulley keyed upon the drive shaft and engagedl by the endless belt 3I. 'This belt also engages the pulley 32 which is keyed upon the spindle I8. y

As shown in Figure 6, the counterslnk and drill parts 5 and 8 respectively of the tool 3 are provided with radial relief, that is the distance between the rear edges 3', 8' is less than that between the front or cutting edges 32, 3. To secure this radial relief, the holder I5 is given a motion toward and away from the abrasive member or grinding wheel 4 at certain predetermined .portions of rotation thereof. To move the tool toward the abrasive. member or grinding wheel, I have provided the handle 33 pivotally mounted upon the base I at the front side of the machine. This handle has preferably integral therewiththe gear sector 34, the teeth of which mesh with the gear sector 35 fixedly secured to the lower part of the rockable support 2. The handle is adapted to be manually operated and by moving the handle downwardly it is apparent that the support 2 will be rocked upwardly from inoperative position to the operative position shown in Figure 2 to establish and maintain engagement of the tool 3 with 'the abrasive member or grinding wheel 4. To

force the rockable member in the opposite direction and the tool away froni the abrasive member or grinding wheel, there is the cam 36 which is keyed to the spindle I8 adjacent the pulley 32. This cam is provided with the peripheral cam faces 38', the number of which corresponds to the number of cutting edges of either the countersink or drill parts of the tool. Cooperating with this cam and engageable with its cam faces is the roller 31 which is journaled upon the arm 38 pivotally mounted at the end opposite the roller upon the support 2 by the pin 39. The roller is yieldably urged outwardly by means of the compression coil spring 40 between the inner side of the arm 38 and the adjacent portion of the support. 4I is a stop mounted upon the base I and engageable with the arm 38 upon rocking of the support 2 to its operative position. 'Ihis stop through the arm compels the roller to engage its associated cam with the result that the support 2 is periodically rocked away from the abrasive member or grinding wheel and periodically allowed to rock toward the abrasive member or grinding wheel tovary the abrasive .effect of .the grinding wheel upon the tool and to thereby provide radial relief.

To vary the radial relief, the stop 4I is adjustable longitudinally of the track 42, which latter is rigidly secured to the base I and extends parallel to the axis of the spindle I8. I'he arrangement is such that this stop in its various positions of adiustment controls the extent of rocking of the support toward thevabrasive member and as a result controls the amount of radial relief. It will be seen that the minimum radial relief will be secured with the stop opposite the axis of the pivot 88 and that the extent of radial relief increases as the stop is adjusted outwardly along the track and away from the pivot.

To form the countersink part 6 of the tool with greater radial relief than that of the drill part 8, I provide the cam 43 and the cooperating member `44 and the compression coil spring 45 for effecting periodic axial movement of the spindle, the holder and the tool away from and toward the abrasive member or grinding wheel. The end of the support 2 opposite the abrasive member or grinding Wheel is formed with the opening 48 therethrough concentric with the spindle I8. 'I'his opening has a reduced inner portion providing the annular shoulder 41 and an enlarged outer portion which is internally threaded. The cam 43 is formed with the annular flange 43 which is clamped against the annular shoulder 41 by the nut 48 threaded into the enlarged Iportion of the opening. The cam preferably extends inwardly beyond the opening and is provided with the cam faces 432 which are engageable by the pins 44 of the member 44. This member is fixedly secured to the spindle I8 and is preferably provided withthe annular flange 442 for extending over and substantially housing the coil spring 45, which latter is located between the member 44 and the adjacent end of one of the bearings I9 for the spindle. The number of cam faces 432 is the same as the number of cutting edges of either of the countersink or drill parts of ,the tool and the timing of both cams 36 and 44 is the same.

The operation of the machine will be apparent from the foregoing disclosure. After the tool has been inserted in the holder the support is rocked towards the grinding wheel by operation of the lever 33. Rocking movement of the support is then controlled by cam 31 which varies the radial relief. 'Ihis radial relief may be varied by positioning stop member 4I with respect to the cam support which is'longitudinally slidable in track 42. At the same time the tool is moved longitudinally of the support topresent it to the grinding wheel and withdraw the tool therefrom by means of cam 43. The latter member is provided with a number of cam faces corresponding with the number of cutting edges on the tool. .In this manner the tool holder is automatically locked on the one hand and reciprocated on the other, not only to provide for radial relief but to alternately present the tool to the wheel and withdraw it during the cutting operation.

From the above description, it will be seen that I have provided a machine which operates t0 accurately grind the tool within very close limits and that the machine is constructed so that its parts are readily accessible. It will also be seen that the machine is provided with an adjustment for varying the extent of radial relief of the tool.

What I claim as my invention is:

1. A machine for grinding cutting tools, comprising an abrasive member, a support rockably movable toward andA away .from saidlabrasivemember, a holder for a tool rotatably carried by said support and adapted to position the tool for engagement by said abrasive member, means for rocking said support toward said abrasive member to establish and maintain engagement of the tool with said abrasive member, a cam rotatable with said holder, a member engageable with said cam upon movement of said support toward said abrasive member to cause said support to periodically move away from said abrasive member, and adjustable means controlling said member for varying the movement of said support toward said abrasive member.

2. A machine for cutting tools, comprising a base, a rockable support, a tubular pivot member ilxedly secured to said support and journaled in said base, a drive shaft extending through said pivot member and journaled on said base, an abrasive member, a holder for a tool rotatably carried by said support, means for rocking said support toward said abrasive member to establish engagement of the tool. with said abrasive member, and means for rotating said holder from said drive shaft.

3. A machine for grinding cutting tools, comprisinga base, a journal member on said base, a support rockably pivoted in said journal, a holder for the .cutting tool in said support, said holder so gripping said tool that the axis of the tool is in spaced and parallel relation to the axis Y of said journal, means for rotating said holder, means for automatically rocking said support and reciprocating said holder during the grinding operation, and means for varying the rocking movement of the support.

4. A machine for grinding cutting tools, comprising an abrasive member, a support movable toward and away from said abrasive member, a holder for a tool rotatably carried by said support and adapted to position the tool for engagement by said abrasive member, means for moving said support toward said abrasive member to establish and maintain engagement of the tool with said abrasive member, a cam rotatable with said holder, a pivotal arm, a roller upon said arm engageable with said cam upon movement of said support toward said abrasive member and operable to cause periodic movement of said support away from said abrasive member, and a stop adjustable in a direction transversely of the movement of said support toward said abrasive member and engageable with said ar'm to limit pivotal movement thereof, said stop being operable to vary the movement of said support toward said abrasive member.

5. A machine for grinding cutting tools, comprising an abrasive member, a base, a rockable support upon said base, a holder for a tool rotatably carried by said support and adapted to position the tool for engagement by said abrasive member, -means for rocking said support toward said abrasive member to establish and maintain engagement of the tool with said abrasive member, a cam rotatable with said holder, a member pivotally mounted upon said support and engageable with said cam upon rocking of said support toward said abrasive member, and a stop upon said base adjustable in a direction transversely of the rocking movement of said support and adapted to limitpivotal movement of said member, whereby rocking of said support toward said abrasive membermay be varied.

6. A machine for grinding cutting tools, comprising an abrasive member operable upon a cutting tool, a member rotatably carrying the tool and movable in a direction to move the tool into engagement with said abrasive member, and means controlling the movement of said member to form a portion of the tool with radial relief, said means comprising a cam rotatable in timed relation to the tool, a pivotal member adapted to cooperate with said cam, and a stop adjustable in a direction transversely of the movement of said tool carrying member and engageable with said pivotal member to limit pivotal movement thereof.

7. A machine for grinding tools, comprising an abrasive member having an axially facing portion for engaging a tool, a support having a portion provided with an opening, an axially movable spindle rotatably mounted on said support at one side only of said portion and having an end portion extending through the opening in said portion, a holder for the toolcarriedl by said spindle and adapted to position the tool for engagement by said abrasive member, a cam insertable into the opening and clamped to said support, and a member secured upon said spindle and cooperable with said cam to periodically move said spindle axially to vary the abrasive eiect of said abrasive member. v

STUART A. COGSDILL. 

